Pattern of reduction of ventilatory and occlusion pressure response to carbon dioxide by pentazocine in man.
Mean inspiratory flow, occlusion pressure and end-tidal PCO2 were measured in six healthy, sitting subjects, during breathing air and rebreathing carbon dioxide, before and after pentazocine 0.5 mg kg-1 i.v. and again after naloxone 20 micrograms kg-1. Pentazocine reduced the occlusion pressure and inspiratory flow responses at a given PCO2 during carbon dioxide rebreathing and these effects were antagonized by naloxone. The relationship of inspiratory flow and end-tidal carbon dioxide during rebreathing was used to measure the PCO2 value at which mean inspiratory flow was 1 litres-1. Occlusion pressure at this PCO2 was reduced in all the subjects by pentazocine, suggesting that the generation of inspiratory flow required less muscle activity. This effect was antagonized by naloxone.
D000328:Adult; D002245:Carbon Dioxide / Q000502:physiology*; D006801:Humans; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D010423:Pentazocine / Q000494:pharmacology*; D011312:Pressure; D012123:Pulmonary Ventilation; D012119:Respiration / Q000187:drug effects*
D002245:Carbon Dioxide; D009270:Naloxone; D010423:Pentazocine